Method of remodeling the stern structure of ships



June 21, 1932. M. J. HANLON 1,854,433

METHOD OF REMODELING THE STERN STRUCTURE OF SHIPS Filed July 15, 1951 s Sheets-Sheet 1 WITNESSES v INVENTOR y W v @6962 {Ian/01L v v jwl W ATTORNEY June 21, 1932. M. J. HANLON 1,354,433

METHOD OF REMODELING THE STERN STRUCTURE OF SHIPS Filed July 15. 1951 5 Sheets-Sheet 2 N VENTOR WITNESSES 3 TL N fz't/zae ilk/H 012 Z yo Q n BY M M N I I ATTORNEY June 21, 1932. M, J. HANLON 1,364,433

METHOD 0F REMODELING THE STERN STRUCTURE OF SHIPS Filed July 13, 1931 5 She ets-Sheet s I" n v INVENTOR WITNESSES g/w v BY m y,

ATTORNEY June 21, 1932. M. J. HANLON METHOD OF REMODELING THE STERN STRUCTURE OF sums Filed July 13. 1931 5 Sheets-Sheet 4 9s U2 A $32 wEUNRVMg P MI 6 ATTORNEY \VITNESSES i w June 21,1932. M. J. HANLON 1,56%433 ING THE STERN STRUCTURE OF SHIPS METHOD or REMODEL Filed July 13. 1951 5 Sheets-Sheet 5 0 QO'OQ ATTORNEYS Patented June 21, 1932 V UNITED. STATES" PATENT orr ca manual. .1. namion, or waanawxax, NEW masmr; Assnmoa TO' 3m: nraxoxn s'rnmsnlr coaroaarxox, or NEW YORK, iv; Y.,' a coaromnoxfor namwm METHOD 0] REMODELING THE STERN STBUC'I'UBE IO! BEDS m Application fled July 18,

This invention has general reference to nae val architecture and/or marine engineering, and has more particular reference to an improved stern structure for ships and a meth- 5 0d of remodeling or modifying that class of ships known as the Hog Island Type A, the broad object in view being to effect a substantial increase in the speed of these vessels with-.

out materially altering the power plant ca- 10 pacity or increasing the fuel consumption.

This class of ships has been open to numerous objections, notably, their lack of speed, which may be mainly attributed to the peculiar construction of the stern portion of the 16 hull which in addition to offering an unusually high resistance or drag, has causeda suc tion. disturbance or turbulence adjacent the propeller, resulting in a reduction of the pro: pulsion efiiciency. The type of rudder employed on these ships also ofl'ersa further resistance to the forward motion of the ship and renders the steering and maneuverin of the ship difiicult while subjecting the ru der and steering gear to undue strains, frequently resultin in fracturing or other damage to the rud ers and steering gear. 1

These and other disadvantageous features have combined to render this type or class of craft ineflicient and, hence, unprofitable to operate in their original condition, and, hence, the present invention comprehends an improved stern structure and a method of correcting the existing defects at a minimum exnditure of time, labor and material.

' With the above recited andother objects in view, the invention resides in an improved stern structure and a method of remodeling or modifying ships of this class, which method is clearly set forth in the following description and illustrated in the accompanying drawings, in which several alternative structures and methods'are setforth, while the claims cover the actual scope of the invention. In the drawings:

Figure 1 is a fragmentary side view of the stern portion of a ship of the typespecified,

illustrating the same modified or, remodeled .60 in accordance with the present invention.

be ow the propeller. 1 F'gure 9 is a fragmentary longitudinal seciaai. Serial No. 550,549.

Figure 2 is a similar view of this type of shi as originally constructed. I a

igure 3 is an enlarged fragmentary'lon itudinal sectional view illustrating the mo ified or remodeled construction.

Figure 4 is a horizontal sectional view taken a roximately on the line indicated at 4- 4in igurel. 1 y f Figure 5 is a horizontal sectional view through the improved rudder, taken approximately on the line indicated at 55 in Figure 1.

Fi ure 6 is a vertical fragmentary sectiona view taken approximately on the line 66 of Figure l, and illustrating. the connection between the rudder and rudder post.

Figure 7 is a horizontal sectional view taken approximately on the line 7-7 of Figure 1, andillustrating the modified contour of the stern frame above the propeller.

Figure 8 is a similar view taken a proxi- .mately on the line 88 of Figural, i ustrat-f in the modified contour of the stern frame tional view of themodifiedstern frame, il-

lustrating an alternative method of accomplishing the remodeling.

Figure 10 is a fragmentary horizontal sec-- tiona view taken approximately on the line a 10-10 of Figure 9'. y 1

v Figure 11 is'a transverse diagrammatic horizontal sectional view taken. approximately on the line indicated at 11-11 in Fi re 3. f f

igure 12 is a ra enta side view 0 a further modification l Figure 13 is an enlarged horizontal sectional view taken approximately on the line 13-13 of Figure 12. i

Figure 14 is a similar horizontal section taken approximately on the line 14.14 of Figure 12. a

In order to illustrate the t' ofship to a which the present method app ies, Figure 2 discloses what is known as the H Island Type A class of ship, in which t portion A of the hull structure Bis provided -with a depending rudder stocksupportingr member 0, the forward face D of which is 9 this point whereby to eliminate trouble which blunt or rounded and merges into a propeller accommodating arch E which merges into the rear or following stern ortion F which is'also blunt or rounded. be propeller G located immediately aft of the stern frame line F on the type of stern construction illustrated, has been found to lack propulsion efiiciency, due to the'suction disturbance or turbulence created by the suction or drag resulting from the blunt or rounded stern line F, in addition to the turbulence created by the forward face D of the depending portion or horn C, as well as the disturbance caused by the blunt leading edge H of the rudder I. In addition to this, the edge F caused a drag or suction while the face D of the horn C and the forward edge of therudder H ofiered a considerable resistance.

In order to overcome or correct the deficiencies above noted whereby to obtain an increased s eed without increasing the power plant or filel consumption, the following method of remodeling or modifying the vessel has been. devised, and said" method consists in first cutting off or removing the depending or horn portion C of the stern frame approximately along the broken line J illustrated in Figure 2. The steel casting 15 or its equivalent is fitted inside the hull and extends horizontally and at a tangent to the remaining portion of the arch E. The steel casting 15 may be provided with arms 16 extendingover a large area of the shell plating to provide an effective method of fastening and also to strengthen the hull at has existeddue to excessive straining and vibration. The casting 15 has attached therei to the plating 17 which is also riveted or otherwise secured as at 18 to the stern por-'.

tion A to provide an eflicient streamline configuration and improve the speed length ratio of the hull at this point. I'he casting is also formed with an upstanding internal tubular boss 19 having an internal bushing 20 to provide a bearing-of ample proportions which is suitable for the increased diameter of a new rudder post or shaft 21. The ordinary form of rudder indicated at I is discarded anda new design of streamline spade form rudder 22 will be fitted to the rudder post, as illustrated in Figure 3. The rudder 22 includes a rudder stock 23 extending the full length or height of the rudder and formed with curved arms 24, to which a steel shell 25 is suitably secured to define a cross sectionallv horizontal streamline con iguration, the rudder stock being disposed approximately one-third of the breadth of the rudder measured from its forward or leading edge 26. The-method furtherconsists in fitting and securing a streamline shell 27 in the propeller arch above the propeller and a streamline shell construction 28 to the hull below the propeller to produce efiicient flow conditions forwardly of the propeller. The shells or forms 27 and 28 as illustrated provide rearwardly converging outer surfaces which make for a minimum of suction disturbance as the hull moves through the water and which further function to improve the speed length ratio of the hull at these points. The method further consists in increasing the efficiency of the propeller G by substituting a new tail-shaft 29 of greater length, so as to relocate the propeller rearwardly in a position remover. as much as possible from the area influenced by hull suction disturbance. This position will be as close as possible to the forward or leading edge of the new rudder 26 and at a point approximating the locus of intersection of the after end of the waterplane lines on a horizontal section through the'center of the propeller shaft.

.This will locate the driving faces of the propeller blades as close as possible to the forward edge of the rudder, which is highly desirable in that the ropeller slip will be decreased to increase t e propulsive efiiciency. It will also be found that t 10 jet or wake of the propeller will be intersected by the rudder and deprived of its rotary motion and will thus be constrained to move away from the propeller in approximately a straight direction with very little rotary motion in the propeller jet. This will result in a reactive thrust on the propeller blades which becomes a component of and increases the total propeller thrust, resulting in an increase in sp ed with a minimum consumption of power and fuel. In order to strengthen and support'the outboard portion of the new tail-shaft a stern tube and outboard bearing 30 will be designed with an extension 31 also be fitted and installed adjacent the in-- neror forward end of the tail-shaft and will carry the usual stufiing box. By following this method, it will be found that the alteration or modification to the vessel may be accomplished at a minimum expense of time, labor and material.

An alternative of certain of the steps of the previously described method is illustrated in Figures 9 and 10, in which instance the existinginefiicient stern frame construction including the depending portion or horn C, the arch E and stern frame F are removed in their entirety and in lieu thereof, there is fitted and installed anew cast steel stern frame 33 which is fashioned as at 34 to produce the streamline effect obtained by the streamline shell 27, and

replaced by a completely new stern structure joins the re-modeled upper portion of the hull. A streamline rudder blade is attached to a rudder stock 46 which is ournaled in bearings 47 formed on the stationary rud-- der nose 43. A rudder post is secured to the rudder blade, as at 49, for controlling the movement of the rudder through the medium of a steering gear not shown.

The propeller 50 is re-located rearwardly in the propeller opening 51 defined between the skag 42, the portions -10, il, and 44, of

the hull and the rudder nose 43. The propeller hub cap 52 is substantially frustoconical and tapers rearwardly and extends into close proximity to the nose 43 of the rudder, the said nose being formed with a substantially conical rearwardly tapering boss 53 disposed in axial alignment with the hub cap. The forward end of the boss 53 and the rear end of the propeller hub cap are of substantially the same diameter, and this coupled with their close proximity, makes the boss in effect serve as a continuation of the hub cap and functions to reduce the suction disturbance of the propeller hub and hub cap. In this construction, as in those previously described. the propeller is located at the locus or intersection of the water plane lines and at the point of least disturbance where the propeller blades work in solid water, thereby eliminating propeller slip and obtaining a maximum of propulsion eiliciency.

\Vhile there have been illustrated and described several improved structures and methods of remodeling or modifying a vessel of the type specified, it is to be understood that other variations and modifications which fall within the scope of the claims may be resorted to when desired.

What is claimed is:

l. A method of modifying a ship of the type specified in order to decrease the hull resistance and improve the propeller propulsion efficiency consisting in removing the depending rudder post supporting portion of the stern frame, substituting for the old rudder a new spade type rudder of streamline horizontal cross section, relocating the propeller rearwardly, adding material to the stern frame above and below and in advance of the relocated propeller to provide a streamline following edge for reducing the suction disturbance and drag and for improving the speed length ratio of the hull.

2. A method of modifying a ship of the type specified in order to decrease the hull resistance consisting in removing the depend ing rudder supportingportion of the stern frame, substituting a streamline spade rudder for the old rudder and adding material to the stern frame above and below the propeller to provide convergent surfaces for decreasing the drag or suction disturbance to a minimum. e I I 3. A method of modifying a ship ofthe type specified asand for the purpose set forth consisting in removing the depending rudder supporting portion of the stern'frame, fitting within the hull portion above the removed dependingportion of the stern frame, a casting having a rudder post bearing of increased proportions, substituting for the old rudder a streamline spade rudder having a rudder post of increased diameter, adding a streamline shell material to theaft portion of the hull above and around said casting and adding material to the stern frame. above and below the propeller to provide convergent surfaces for decreasing the'drag or suction disturbance to a minimum.

4. A method of modifying a ship of the type specified as and for the purpose set forth consisting in removing the depending rudder supporting portion of the stern frame, fitting within. the hull portion above the removed depending portion of the stern frame, a casting having'a rudder post bearingof increased proportions, substituting for the old rudder a streamline spade rudder having a rudder post of increased diameter. adding a streamline shell material to the after portion of the hull above and around said casting, relocating the propeller aft at a point closely, adjacent the entering edge of the rudder and adding material to the stern frame above and below the propeller to provide convergent surfaces for decreasing the drag or suction disturbance to a minimum.

5. A method of remodeling a ship of the class specified as and for the purpose set forth including the steps of removing the depending rudder portion of the stern frame, fitting and securing to the stern in the propeller arch above the propeller and below the propeller, streamline shells for reducing the drag and producing efficient flow conditions forward of the propeller. v

6. A method of remodeling a ship of the class specified as and for the purpose set forth including the steps of removing the dependin g rudder portion of the stern frame,fitting and securing to the stern in the propeller arch above the propeller and below the propeller, streamline shells for reducing the drag and producing efficient flow conditions forward of the propeller and relocating the propeller rearwardly at the point of minimum suction disturbance.

7 A method of remodeling a ship having a propeller and a blunt round stern portion immediately in front of the propeller consisting in moving the propeller rearwardly-to the point of minimum suction disturbance and in applying streamline shell plates to said blunt stern pro erly proportioned to substantially destroy t e drag caused by said blunt stern and the turbulence of the water adjacent the propeller.

8. A method of remodeling a ship having a propeller and a blunt round stern portion immediately in front of the propeller consisting in moving the propeller rearwardly to the point of minimum suction disturbance and in reconstructing said blunt stern to lengthen the same and present streamline sides converging at a point immediately in front of the propeller.

9. A method of remodeling the stern structure of a ship of the class described including the step of removing the depending portion of thestern frame, altering the portion thereabove to increase the size of the rudder post bearing and substituting for the old rudder a new rudder of horizontal cross sectional streamline configuration having a rudder post of increased diameter.

10. A method of remodeling the stern structureof a ship of the class described including the step of removing the depending portion of the stern frame, altering the portion thereabove to increase the size of the rudder post bearing and substituting for the old rudder a new rudder of horizontal cross sectional streamline configuration having a rudder post-of increased diameter and having its axis disposed approximately one-third of the rudder breadth from the forward edge.

MICHAEL J. HANLON. 

